1. Field of the Invention:
The present invention relates generally to a method and an apparatus for transmitting and receiving data in a wireless communication system. More particularly, the present invention relates to a method and an apparatus for reducing data retransmission repeated by a MAP message reception failure when resources are reallocated in a wireless communication system based on a superframe.
2. Description of the Related Art:
A 4th generation (4G) communication system, which is a next-generation communication system, provides users with services of various Quality of Service (QoS) levels at a data rate of about 100 Mbps. Representative examples include an Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard system. The IEEE 802.16 standard system adopts Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) scheme to support a broadband transmission network in physical channels.
In a broadband wireless communication system such as IEEE 802.16 standard system, a base station allocates resources to terminals to transmit and receive packets. The base station transmits to the terminal, a resource allocation MAP) message indicating resource allocation results such as a location, a size, a modulation scheme, and a code rate of the allocated resource over a downlink channel. In general, a message indicating the resource allocation results for uplink communication and a message indicating the resource allocation results for downlink communication are separately generated. The information unit for one resource allocation is referred to as a resource allocation Information Element (IE).
The resource allocation targets at the resources within a certain region. Since the resource for general data packets is allocated per regular region, the relevant resource allocation IE is transmitted per regular region. However, in a Voice over Internet Protocol (VoIP) service delivering packets on a periodic basis, having the MAP IE included in every packet transmission causes unnecessary resource waste. Accordingly, the packet of the periodic transmission period such as a VoIP packet applies a persistent allocation scheme which reduces the resource waste caused by the resource allocation IE by persistently allocating the resources. According to the persistent allocation scheme, the downlink communication transmits the resource allocation IE and the packet only in an initial resource allocation, and then only the packets are transmitted without the resource allocation IE. Hence, the terminal using the persistently allocated resource continues using the persistently allocated resource without the resource allocation IE until deallocation information or allocation change information is received. When the existing allocation information is modified, the persistent allocation scheme should transmit the resource allocation IE for a new persistent allocation. The persistently allocated resources are deallocated when the deallocation information of the VoIP packet is received.
When the persistent resource allocation in the IEEE 802.16m standard uplink is to be modified, the base station transmits to the terminal the MAP for reallocating the persistently allocated resource. When the persistent resource reallocation MAP is not received, the terminal transmits the persistently allocated packet using the previous resource allocation information, and the base station transmits a Negative ACKnowledgement (NACK) for the transmitted packet. Even when the base station recognizes that the terminal fails to receive the persistent resource reallocation MAP, the persistent resource reallocation MAP is unable to be transmitted to the terminal until the next persistent resource allocation period. That is, the terminal repeats the retransmission until the next persistent allocation period and thus the resources of the terminal are wasted.
Therefore, a need exists for addressing failure of a persistent resource reallocation MAP reception of a terminal for an uplink.